Detector bar



C. D. BROWN DETECTOR BAR May 3o, 1939.

Filed Nov. 9, 1938 a :nimm

mvNToR.

` ATTORNEY.

/JJ BY @EL D. Bean/N.

Patented May 30, 1939 UNITED STATES PATENT OFFICE Draper Corporation,poration of Maine Hopedale, Mass., a cor- Application November 9, 1938,Serial No. 239,665

3 Claims.

The present invention pertains to electric Warp stop motions for loomsand more particularly relates to the detector bars of such stop motions.

Electric warp stop motions of the type to which my invention appliescommonly include a plurality of parallel detector bars which extendwidthwise of the loom across the warp sheet and which are located withinslots or openings in drop wires. Each of such detector bars comprises apair of contact bars o-ne of which has a channel in its upper edge andthe other of which is fixed in said channel but provided with an upperContact edge located above the top edge of the channelled contact bar.The two contact bars are insulated from each other and form theterminals of an electric circuit which is normally open but which isadapted to be closed by any one of the drop wires. The drop wires aresupported by the warp threads and normally contact only the channelledcontact bar. When any warp thread breaks, its corresponding drop wirefalls into engagement with aforesaid upper contact edge, thereby closingthe electric circuit.

Prior to the present invention, the detector bar slots in drop wires foruse with electric warp stop motions were provided with an inclined edge,usually at the top of the slot, for causing a drop wire to movelaterally as it falls. This lateral movement of the dropwire is found tobe necessary to insure good electrical contact between the drop wire andboth of the contact bars. In drop wires for use with mechanical warpstop motions, the aforesaid slots usually have straight sides andsymmetrically rounded tops. It is desirable that electric warp stopmotions be capable of operating with drop wires wherein the detector barslots have rounded tops. This is because such drop wires are cheaper tomanufacture and easier to finish properly, because of the expense andinconvenience of buying and using two .different types of drop wires inmills where both types of Warp stop motion are used, and for otherreasons which need not be enumerated herein.

It is accordingly a principal object of the present invention to providea detector bar for electric warp stop motions which detector bar shallcomprise a channelled contact bar and a second contact bar xed in andinsulated from the channelled bar, as aforesaid, but which secondcontact bar shall have a horizontal upper contact edge which is offsettoward one side of the detector bar, whereby such detector bar may beused with drop wires of the aforesaid type wherein the detector barslots have rounded tops.

The foregoing and other objects of the invention are accomplished in theconstruction illustrated on the accompanying drawing, of which:

Fig. 1 is a view in cross-section ofv an electric warp stop motionincluding the preferred embodiment of my improved detector bars;

Fig. 2 is a detail View, in cross-section, and to a larger scale,showing a drop wire and one of said preferred detector bars; and

Fig. 3 is a view similar to Fig. 2 but showing a modied form of myimproved detector bar.

The warp stop motion shown on the drawing includes suitable supportingbrackets, such as end bracket I, adapted to be fixed to a loom frame,not shown. One such end bracket is provided at each side of the loom,the brackets supporting the warp support members 2 and 3 which extendwidthwise of the loom. Additional members Il, i extending between thebrackets may be provided, for further supporting the warp sheet and forseparating the various rows or banks of drop wires. The particular endbracket I shown is of two-piece construction, the lower piece being xedand the upper piece 5 being supported on vertically adjustable studs 6.The upper piece 5 is provided with slots or the like for receiving theends of the detector bars hereinafter described, and a cap 'I is securedto the piece 5 by nuts 8 on the studs 6, to thereby hold the detectorbars in said slots.

The warp stop motion as thus far described in detail is not of thepresent invention and may be of any suitable usual construction, myinvention pertaining to the detector bars indicated generally at 9, 9 onFig. l. The particular stop motion shown is of so-called four-bankconstruction in that it has four parallel detector bars for receivingfour rows of drop wires I. Each of the drop wires is a sheet metaldevice having an opening II for receiving a warp thread W (see Fig. 2)and a slot I2 for receiving one of the detector bars. The drop wiresoperate in the usual manner in that each drop wire is normally supportedby a warp thread but falls and engages the detector bar in a manner tocomplete an electrical circuit when a warp thread breaks. The drop wiresIl! are of a type heretofore used only in mechanical Warp stop motions,the tops I3 of slots I2 being symmetrically rounded.

Each detector bar is of novel construction and consists of a contact barI4 and a contact bar I5, which contact bars are insulated from eachother. The contact bar I4 consists of side walls I6 and I 'l and abottom portion I3 forming a channel which is open at its top. In otherwords, the

bar I4 extends horizontally across the loom and has a channel in itsupper edge. This bar may be constructed in any suitable manner, but inthe embodiment shown on Figs. 1 and 2 of the drawing the walls I 6 andIl are flat strips of metal which are spaced by and welded to a separatemetal strip which constitutes the bottom portion I8. In this embodiment,the walls I6 and I'I are of rectangular cross-section and are positionedin vertical planes, whereby both the side faces of the detector bar andthe sides of the channel are substantially vertical.

The contact bar I consists of a relatively thin strip of metal which isfixed in and extends generally horizontally along the aforesaid channelin contact bar I4. The contact bar I5 may be xed in said channel in anysuitable manner, but is insulated from the contact bar I4 as byinsulating material I9. The bar I5 is bent along a longitudinal line, toprovide a lower portion (i. e., the portion in said channel) which ispositioned in a vertical plane, and a top contact edge 2G which isoff-set to one side of the vertical axis of the detector bar. As shownmore clearly on Fig. 2, the top edge 20, which extends horizontallyacross the loom, is located above and vertically over the top of wa'llI6. As thus located, the edge 2G is appreciably nearer to the verticalplane containing one side face of the detector bar than to thecorresponding plane containing the other side face thereof. The edge 20is, however, located between said planes in order to prevent itsengaging the side of the slots I?. in the drop wires.

The aforesaid off-setting of the contact edge 2S results in theeflicient cooperation of the detector bar with drop wires having roundedtops I3. More specifically, it will be seen that if the edge 20 werecentrally located with respect to the side faces of the detector bar, afallen drop wire would balance on such edge and would not make goodelectrical contact with the contact bar I4. However, being thus off-set,the edge 20 will first engage a falling drop wire at some point such aspoint 2I (Fig. 2) on the round I3, whereupon the top of the drop wirewill move laterally toward the right on Fig. 2 until the wire contactsthe wall I1.

A modified construction is shown on Fig. 3 of the drawing, thisconstruction including, however, the same drop wire I0 having slot I2and rounded top I3 shown in Figs. 1 and 2. In this construction, thedetector bar includes a Contact bar having side walls 22 and 23 and abottom portion 24. The side walls 22 and 23 are formed from strips ofmetal which are of triangular cross-section and which are so relatedthat the side faces of the Contact bar as a whole are vertical but thesides of the channel in such bar are parallel and inclined to thevertical. Y

The embodiment of Fig. 3 further includes a contact bar 25 which isfixed in the channel in the above-described contact bar and whichconsists simply of a thin, flat strip of metal. The contact bar 25 isfixed in a plane which is parallel to the side Walls of said channel,and is insulated by insulating material 26. As thus constructed, whilethe contact bar 25 is at, the upper horizontal edge 21 thereof isoff-set to substantially the same relative position as contact edge 20in the embodiment previously described. It will be seen that thedetector bar shown on Fig. 3 will operate in the same manner as thedetector bar 9. Neither of the embodiments of detector bar is limited touse with the particular drop wires shown.

Having fully disclosed the preferred embodiment of A'my invention, Iclaim:

l. An electric warp stop motion detector bar comprising a pair ofhorizontal contact bars, one of said contact bars having side walls anda bottom portion forming a channel which is open at its top, the sidefaces of said contact bar being substantially vertical, and the other ofsaid contact bars consisting of a relatively thin strip of metal fixedin said channel and insulated froml the rst said contact bar, said othercontact bar having a horizontal upper edge located above and verticallyover one of said side Walls but between the planes of said side faces.

2. An electric warp stop motion detector bar comprising a pair ofhorizontal contact bars, one of said contact bars having side walls anda bottom portion forming a channel which is open at its top, the sidefaces of both of said side walls being substantially vertical, and theother of said contact bars consisting of a relatively thin i strip ofmetal bent to provide a lower portion positioned within said channelparallel to said side walls and an upper edge portion located above andvertically over the top of one of said side walls, said other contactbar being insulated from the first said contact bar.

3. An electric warp stop motion detector bar comprising a pair ofhorizontal contact bars having insulating material therebetween, one ofsaid contact bars havingside walls and a bottcm portion forming achannel which is open at its top, the sides of said channel beingparallel and vertically inclined, and the other of said contact barsconsisting of a flat strip of metal iixed in said channel in a planeparallel to said inclined sides, said strip having a horizontal top edgelocated vertically over the top of one of said side walls.

' CARL D. BROWN.

